Last week I focused the Purpose and Scope, and the Principles outlined in the Digital Preservation Policy Framework document. This week I will concentrate on the Categories of Commitment and Levels of Preservation portions of the document.
Categories of commitment
- Born digital materials. Examples: ETDs (Electronic Theses and Dissertations), institutional records
- Digitized materials (no available or usable analog). Examples: Unique audio and video from Music/Dance & Special Collections. This category also includes digitized materials that have annotations or other value-added features making them difficult or impossible to recreate.
- Digitized materials (available analog). Examples: TRI Actress scrapbooks, Suyemoto Papers, Rubin Collection of Lantern Slides, and the Lantern.
- Commercially available digital resources. Example: e-journals (Project Muse, JSTOR)
- Other items and materials.
We can’t do everything. These categories are meant to be seen as guidelines. Developing solutions for “born digital” resources informs solutions for other categories. But it does not imply that these assets are more valuable or important than any other categories and/or our traditional analog materials. The categories of commitment add another dimension to discussions of stewardship. For example, digitization of materials that are in danger of format obsolescence, or that depend on superseded equipment, may create an urgency for action, but only if the content of the materials is judged to be essential.
Levels of preservation
In thinking about the preservation of digital objects, it is natural to jump to discussions of “how”. While the framework document does not address the nitty gritty of “how”, the Digital Archiving Maturity Model developed by Tessella Technology and Consulting is useful in thinking the issues. The model is used to imply layers of sophistication in processes. The makers of the model see the process as linear, do level 1 first, then level 2, etc. That may be true for a particular format, but we see a program of preservation working on multiple levels simultaneously.
The model is divided into two main sections:
Durable storage. Layers 1-3 provide increasing levels of sophistication in the safety and security of the storage of the raw bits used to hold information. By the time you have a Level 3 compliant system you can be confident your information will not be lost and that it has not been tampered with.
Information management. Layers 4-6 ensure that the preserved raw bits can be found and interpreted correctly now and in the future. With a Level 6 system your information is organized and searchable, the processes are automated and you can use it as you wish.
- Level 1 – Safe Storage. This is simple bit-level storage. There are multiple means of doing this including using managed locations, and protected long term media.
- Level 2 – Storage Management. Storing information efficiently and retrieving it as required. Moves the bits to the most appropriate location based on storage durability, cost reduction, or performance. These factors need to be balanced.
- Level 3 – Storage Validation. Adds multiple object storage plus fixity checking. Object fixity is checked on storage, and access.
- Level 4 – Information Organization. Incorporates information hierarchy organization, descriptive data management, and simple processes for uploading, locating and downloading information, and basic information security
- Level 5 – Information Processes. Adds business processes to automate the activities associated with information management. These include interfaces to information sources and dissemination to consumers using flexible workflows and programmer interfaces. Also includes integration with a third party identity management system.
- Level 6 – Information Preservation. At this level, systems add capabilities to ensure that the information stored is usable when it is needed by the audience that requests it. This is complex as file formats and applications that can read them are short lived and fragile.
During the Admin Plus presentation, SDIWG led a discussion of the complex issues surrounding digital exhibits to illustrate the levels of preservation. Below are some of the questions discussed:
- What needs to be preserved? Are we preserving the items, the scholarship, and/or the experience?
- Do the parts need to be stored together? Do we need to preserve the exhibit as a single whole? Such an approach means that the Libraries would be preserving multiple copies or versions of “objects” used in the exhibit. Is this efficient or scalable?
- What is a master, what is a derivative?
- How can we automate the management and linking of related files?
- How can we preserve the structure of the exhibit in order to recreate it?
- How can we automate delivery of content in the format needed at time of use?
We encourage you to keep a link to the framework document handy! More importantly, think about how the ideas in the framework affect your work with digital materials and how they might help you collaborate with colleagues in the curation of these important resources.